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  • 1.
    Alirezaie, Marjan
    et al.
    Örebro University, School of Science and Technology.
    Loutfi, Amy
    Örebro University, School of Science and Technology.
    Reasoning for Improved Sensor Data Interpretation in a Smart Home2014Conference paper (Refereed)
    Abstract [en]

    In this paper an ontological representation and reasoning paradigm has been proposed for interpretation of time-series signals. The signals come from sensors observing a smart environment. The signal chosen for the annotation process is a set of unintuitive and complexgas sensor data. The ontology of this paradigm is inspired form the SSNontology (Semantic Sensor Network) and used for representation of both the sensor data and the contextual information. The interpretation process is mainly done by an incremental ASP solver which as input receivesa logic program that is generated from the contents of the ontology. The contextual information together with high level domain knowledge given in the ontology are used to infer explanations (answer sets) for changes in the ambient air detected by the gas sensors.

  • 2.
    Andersson, Birgitta
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Long term charge retention on PWBs2005Conference paper (Other academic)
    Abstract [en]

    A sample of printed wiring boards, isolated from ground, has been charged tribo-electrically and the charge decay process has been studied with focus on the long-term charge decay behaviour. It was found that the time constant 1/e did not say much about the proceeding decay process. Instead a second-order approximation model for the measured decay curves has been suggested.

  • 3.
    Andersson, Birgitta
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Long term charge retention on PWBs2005Conference paper (Other academic)
    Abstract [en]

    A sample of printed wiring boards, isolated from ground, has been charged tribo-electrically and the charge decay process has been studied with focus on the long-term charge decay behaviour. It was found that the time constant 1/e did not say much about the proceeding decay process. Instead a second-order approximation model for the measured decay curves has been suggested.

  • 4.
    Andersson, Birgitta
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Remote monitoring of Electrostatic Charges in an EPA2007Conference paper (Other academic)
  • 5.
    Bergström, Per
    et al.
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Khodadad, Davood
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Hällstig, Emil
    Optronic Partner Dp AB, Skellefteå, Sweden.
    Sjödahl, Mikael
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå, Sweden.
    Dual-wavelength digital holography: single-shot shape evaluation using speckle displacements and regularization2014In: Applied Optics, ISSN 1559-128X, E-ISSN 2155-3165, Vol. 53, no 1, p. 123-131Article in journal (Refereed)
    Abstract [en]

    This paper discusses the possibility of evaluating the shape of a free-form object in comparison with its shape prescribed by a CAD model. Measurements are made based on a single-shot recording using dual-wavelength holography with a synthetic wavelength of 1.4 mm. Each hologram is numerically propagated to different focus planes and correlated. The result is a vector field of speckle displacements that is linearly dependent on the local distance between the measured surface and the focus plane. From these speckle displacements, a gradient field of the measured surface is extracted through a proportional relationship. The gradient field obtained from the measurement is then aligned to the shape of the CAD model using the iterative closest point (ICP) algorithm and regularization. Deviations between the measured shape and the CAD model are found from the phase difference field, giving a high precision shape evaluation. The phase differences and the CAD model are also used to find a representation of the measured shape. The standard deviation of the measured shape relative the CAD model varies between 7 and 19 μm, depending on the slope.

  • 6.
    Birkelöf, Jonas
    Örebro University, School of Science and Technology.
    Framtagning av demonstratorer2009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    På Alfred Nobelmuseet i Karlskoga finns en avdelning som kallas Fiffiga huset. Där finns många experiment som besökare kan prova på, samt montrar som visar hur olika tekniska och maskinella apparater fungerar. Till utställningen och öppnandet sommaren 2009 ville de ha två nya demonstratorer. I rapporten kallas dem för reaktionstidsväggen och baklängesprataren. Reaktionstidsväggen skulle mäta besökarens reaktionstid genom att tryckknappar, med inbyggda dioder som slumpvis tänds, trycks ned i rätt ordning. Baklängesprataren skulle spela in besökarens tal och sedan spela upp det baklänges. Tanken var att besökaren skulle försöka prata baklänges och få det att låta rätt vid uppspelning. Arbetet gick ut på att bygga dessa demonstratorer och montera dem i Fiffiga huset. Reaktionstidsväggen styrdes med hjälp av en mikroprocessor ATMega16 från Atmel. Dess jobb var att läsa av knapptryckningar samt skicka information till dioder och display. Även baklängesprataren skulle styras med hjälp av mikroprocessorn ATMega16. En enkel mikrofonförstärkare samt filter till högtalarna skulle anslutas till processorn. Det inbyggda minnet skulle inte räcka till så ett extern minne behövde anslutas.Endast reaktionstidsväggen hann bli färdig inom projektets ramar eftersom all gammal elektronik som medföljde från Nobelmuseet var komplex, samt att många kortslutningar och avbrott gjorde felsökning till en tidskrävande procedur.

  • 7.
    Boustedt, Katarina
    et al.
    Örebro University, School of Science and Technology.
    Persson, Katrin
    IMEGO, Gothenburg, Sweden.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Flip chip as an enabler for MEMS packaging2002In: 52nd Electronic Components and Technology Conference, 2002. Proceedings., 2002, p. -128Conference paper (Refereed)
    Abstract [en]

    With the recent trends in microelectronics to move more and more towards incorporating MEMS (micro electro mechanical systems) structures, lowering the overall cost becomes vital. One major cost driver in today's MEMS is the packaging. Many of the MEMS structures require some level of low pressure for full quality operation, and some may even need vacuum to function properly. Different MEMS packaging strategies exist on the market and they can be divided into two different approaches. The first one protects the wafer temporarily during wafer scribing or dicing and the second one provides a permanent seal to the wafer through full wafer bonding before scribing and dicing. The latter, permanent methods allows for selecting very low cost packaging without hermeticity as a requirement, whereas in the temporary seal methods the seal is removed after dicing and the sensitive structures become unprotected again. Using flip chip for MEMS has the benefit of providing MEMS structures with a covering lid, the chip itself. A number of flip chip MEMS interconnection methods presented in literature are described.

  • 8.
    Boustedt, Katarina
    et al.
    Örebro University, School of Science and Technology.
    Persson, Katrin
    IMEGO, Gothenburg, Sweden.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Bohman, Sofie
    IMEGO, Gothenburg, Sweden.
    Wafer Bonding Technologies for MEMS Packaging2002In: Proceedings : the IMAPS Nordic Annual Conference : Stockholm, 2002, 29 September-2 October 2002., 2002, p. -127Conference paper (Other academic)
  • 9.
    Carlsson, Johannes
    Örebro University, School of Science and Technology.
    Digital ljudkvalitetsoptimering för hörlurar.2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete har utförts hos Dirac Research AB i Uppsala. Dirac Research är en världsledande programvaruspecialist inom ljudoptimering, rumskorrigering och ljudfältssyntes.

    Dirac har nu velat utreda hur man på bästa sätt kan använda deras programvara Dirac Live för att förbättra ljudet hos hörlurar. I examensarbetet ingick en teoretisk del om örat, hörlurar, mätmetoder och hur en frekvenskurva bör se ut. Det ingick också att mäta impulssvaret för några olika hörlurar. Impulssvaret användes sedan till att förbättra ljudet hos hörlurarna genom att designa digitala filter som användes genom programvaran Dirac Live. När filterdesignen var klar utfördes ett lyssningstest för att få åsikter om hur andra upplevde filtrena.

    Mätningarna utfördes på Karolinska Institutet i Huddingen på ett KEMAR-huvud. Det är ett konsthuvud som ska efterlikna en människas huvud till form och storlek. Där mättes fyra earbuds (intra-concha), tre in-ear (insert), två omslutande (circum-aural) och ett par utanpåliggande (supra-aural) hörlurar upp. Med filterdesignen visade det sig att förbättringar upplevdes på de flesta av hörlurarna. Dock så kompenserades inte de omslutande- och utanpåliggande hörlurarna något. Dessa var endast tänkta att ha som referens.

    Det var en del skillnader mellan de olika hörlurarnas frekvenssvar. Det beror delvis på hörselgångens resonansfrekvens. När omslutande hörlurar mäts kan hörselgången ses som en kvartsvågsresonator medan den vid mätning av in-ear-hörlurar kan ses som halvvågsresonator. Även hörlurarnas konstruktion påverkar skillnaderna för de olika hörlurstyperna.

    Som målkurvor till hörlurarna användes bland annat högtalarmätningar i form av frifältsmätningar och diffusfältsmätningar utöver de hörlurar som användes som referens. Dock upplevdes en frekvensgång med en mjuk topp vid 3 kHz och i övrigt ganska rak frekvensgång som bäst. Vid lyssningstestet var det även den kurvan som fick flest röster hos tre av de fyra hörlurarna som användes vid lyssningstestet.

  • 10.
    Chatzipetrou, Panagiota
    et al.
    Software Research Engineering Lab (SERL), Blekinge Institute of Technology, Karlskrona, Sweden.
    Alégroth, Emil
    Software Research Engineering Lab (SERL), Blekinge Institute of Technology, Karlskrona, Sweden.
    Papatheocharous, Efi
    RISE SICS AB, Lund, Sweden.
    Borg, Markus
    RISE SICS AB, Lund, Sweden.
    Gorschek, Tony
    Software Research Engineering Lab (SERL), Blekinge Institute of Technology, Karlskrona, Sweden.
    Wnuk, Krzysztof
    Software Research Engineering Lab (SERL), Blekinge Institute of Technology, Karlskrona, Sweden.
    Component selection in Software Engineering: Which attributes are the most important in the decision process?2018In: 44th Euromicro Conference on Software Engineering and Advanced Applications, SEAA 2018: Proceedings / [ed] Bures, T; Angelis, L, IEEE conference proceedings , 2018, p. 198-205Conference paper (Refereed)
    Abstract [en]

    Component-based software engineering is a common approach to develop and evolve contemporary software systems where different component sourcing options are available: 1)Software developed internally (in-house), 2)Software developed outsourced, 3)Commercial of the shelf software, and 4) Open Source Software.

    However, there is little available research on what attributes of a component are the most important ones when selecting new components. The object of the present study is to investigate what matters the most to industry practitioners during component selection. We conducted a cross-domain anonymous survey with industry practitioners involved in component selection. First, the practitioners selected the most important attributes from a list. Next, they prioritized their selection using the Hundred-Dollar ($100) test. We analyzed the results using Compositional Data Analysis. The descriptive results showed that Cost was clearly considered the most important attribute during the component selection. Other important attributes for the practitioners were: Support of the component, Longevity prediction, and Level of off-the-shelf fit to product. Next, an exploratory analysis was conducted based on the practitioners' inherent characteristics. Nonparametric tests and biplots were used. It seems that smaller organizations and more immature products focus on different attributes than bigger organizations and mature products which focus more on Cost.

  • 11.
    Ericsson, Niclas
    et al.
    RISE SICS, Västerås, Sweden.
    Lennvall, Tomas
    Örebro University, School of Science and Technology. RISE SICS, Västerås, Sweden.
    Åkerberg, Johan
    ABB AB Corporate Research, Västerås, Sweden.
    Björkman, Mats
    School of Innovation Design and Technology, Mälardalen University, Västerås, Sweden.
    A flexible communication stack design for time sensitive embedded systems2017In: 2017 IEEE International Conference on Industrial Technology (ICIT): Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1112-1117Conference paper (Refereed)
    Abstract [en]

    Trends like Internet of Things (IoT), 5G and Cloud are pushing for device connectivity to the Internet, which affects industrial embedded systems with e.g., an increase in code base and functionality. Due to different application requirements, there are relative little reuse between embedded systems with different run-time context (from super loop to multi-threaded), and different types of communication (best effort and real time). In order to improve code reuse and changeability, we propose a flexible communication stack design, that can be configured for time sensitive communication with a real-time operating system (RTOS), or configured for best effort communication with either a super loop or an operating system (OS). Experiments demonstrate the flexibility and simplicity of the design with different configurations, e.g., super loop, single threaded, multi-threaded. Measurements show that the variations in performance related to run-time context scales as expected.

  • 12.
    Gidlund, Mikael
    et al.
    Mid Sweden University, Västerås, Sweden.
    Lennvall, Tomas
    RISE SICS, Västerås, Sweden.
    Åkerberg, Johan
    ABB AB Corporate Research, Västerås, Sweden.
    Will 5G become yet another wireless technology for industrial automation?2017In: 2017 IEEE International Conference on Industrial Technology (ICIT): Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1319-1324Conference paper (Refereed)
    Abstract [en]

    With the growing interest in adoption of wireless technologies in industrial automation and the continuous search for new revenue streams new players are entering the arena in order to make their business grow further. One of the emerging wireless technologies aiming to support industrial automation applications is 5G, targeting anything from extreme throughput (> 10 Gbit/s) to extreme low latency (≤ 1 ms) to ultra high reliability (≥ 99.999%). In this article we intend to discuss the potential and challenges of adopting 5G in real industrial environments and give a more balanced picture compared to previous articles mainly written by telecom researchers and vendors as a way to promote their technology. Specifically, this article will discuss and provide some real industrial requirements, describe the main technical features of 5G and try to assess what applications it will support that are not by already supported by existing technologies. In the end, the success of 5G will depend on appealing business models and scalability, i.e., whether or not the same equipment can be deployed worldwide without any changes and spectrum rules, and the migration paths beyond 5G for reasonable business risks.

  • 13.
    Hassanzadeh, Rahman
    Örebro University, School of Science and Technology.
    UTVECKLING AV PROCESSORPLATTFORM2007Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

     

    The purpose of this project is to develop a modular processor card which is intended to work as a platform for Kitron Development Karlskoga. The modular processor card is meant to be used as a control system in development projects, mainly in medical and industrial products. The processor card will consist of a central unit with the basic functions for a control system. Furthermore there will be complete modules with machine commodity and programming, to pick exactly the necessary functions for a specific application.

     

    With consideration to the specification of the development and the main unit, I chose an adequate microprocessor (AT90CAN32) as core and interface circuits to stated border areas.

     

    The construction is first completed in the program MultiSim and then remade in the program OrCAD Capture. The programming language C was used in the software model. Then a layout was created in the program Ultiboard.

     

    The project has resulted in the manufacture of a pattern card that can manage I/O units, such as D/A-converter, keyboard, display and serial port RS-232. The purpose was that the units should communicate with the processor. The application decides what the main unit is used for.

     

    The D/A-converter was governed through SPI commands and the result was shown on an instrument (voltage). With the keyboard I was able to write digits to the processor and the result was shown on the display. The keyboard was used to send digits to the processor and was then sent through RS-232 to the PC. In the PC, a terminal program was used to receive digits.

     

    A general platform has been developed through this project, where you can choose which functions you wish to use (see the building block in figure no.1).

  • 14.
    Hüllmann, Dino
    et al.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Kohlhoff, Harald
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Erdmann, Jessica
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Neumann, Patrick P.
    Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Germany.
    Current-independent torque control of permanent-magnet synchronous motors2017In: Materials Today: Proceedings, E-ISSN 2214-7853, Vol. 4, no 5, p. 5821-5826Article in journal (Refereed)
    Abstract [en]

    A current-independent torque equation for the permanent-magnet synchronous motor (PMSM) aiming at direct-drive servo applications is derived from a first principles model. Instead of measuring currents, all required control parameters are derived from optical incremental encoder measurements. The results are verified on a real system in test series showing the effect of static friction and proving the obtained torque model.

  • 15.
    Kaltenhaeuser, Robert
    et al.
    Ilmenau University of Technology, Ilmenau, Germany.
    Schaffernicht, Erik
    Örebro University, School of Science and Technology.
    Steege, Frank-Florian
    Ilmenau University of Technology, Ilmenau, Germany.
    Gross, Horst-Michael
    Ilmenau University of Technology, Ilmenau, Germany.
    Evolutionary computation based system decomposition with neural networks2013In: ESANN 2013 proceedings, European Symposium on Artificial Neural Networks, Computational Intelligenceand Machine Learning, Louvain-La-Neuve: ESANN , 2013, p. 191-196Conference paper (Refereed)
    Abstract [en]

    We present an evolutionary approach to divide a complex control system into smaller sub-systems with the help of neural networks.Thereto, measured channels are partitioned into several disjunct sets, rep-resenting possible sub-problems, while the networks are used to assessthe quality of the resulting decomposition. We show that this approach iswell suited to calculate correct decompositions of complex control systems.Furthermore, the obtained neural networks are used to predict importantprocess factors with considerable better approximation quality than mono-lithic approaches that have to deal with all input channels in parallel.

  • 16.
    Karlsson, Tobias
    et al.
    Örebro University, School of Science and Technology.
    Linnér, Jakob
    Örebro University, School of Science and Technology.
    Avfyrnings-/relälåda2009Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a report of our examination project in electronics carried out for Bofors Test Center in Karlskoga. The task was to construct an electronic devise for starting up different kinds of measuring systems in exact time during test sequences. The modules that are used today are old and unreliable. Our goal was to construct a prototype, which later on is supposed to be developed into a useful system.

  • 17.
    Khodadad, Davood
    et al.
    Luleå University of Technology, Luleå, Sweden.
    Amer, Eynas
    Luleå University of Technology, Luleå, Sweden.
    Gren, Per
    Luleå University of Technology, Luleå, Sweden.
    Melander, Emil
    Uppsala University, Uppsala, Sweden.
    Hällstig, Emil
    Fotonic, Stockholm, Sweden.
    Sjödahl, Mikael
    Luleå University of Technology, Luleå, Sweden.
    Single-shot dual-polarization holography: measurement of the polarization state of a magnetic sample2015In: VI International Conference on Speckle Metrology, SPIE - International Society for Optical Engineering, 2015, Vol. 9660, article id 96601EConference paper (Refereed)
    Abstract [en]

    In this paper a single-shot digital holographic set-up with two orthogonally polarized reference beams is proposed to achieve rapid acquisition of Magneto-Optical Kerr Effect images. Principles of the method and the background theory for dynamic state of polarization measurement by use of digital holography are presented. This system has no mechanically moving elements or active elements for polarization control and modulation. An object beam is combined with two reference beams at different off-axis angles and is guided to a detector. Then two complex fields (interference terms) representing two orthogonal polarizations are recorded in a single frame simultaneously. Thereafter the complex fields are numerically reconstructed and carrier frequency calibration is done to remove aberrations introduced in multiplexed digital holographic recordings. From the numerical values of amplitude and phase, a real time quantitative analysis of the polarization state is possible by use of Jones vectors. The technique is demonstrated on a magnetic sample that is a lithographically patterned magnetic microstructure consisting of thin permalloy parallel stripes.

  • 18.
    Khodadad, Davood
    et al.
    Luleå University of Technology, Luleå, Sweden.
    Hallstig, Emil J.
    Optronic, Skellefteå, Sweden.
    Sjödahl, Mikael
    Luleå University of Technology, Luleå, Sweden.
    Dual-wavelength digital holographic shape measurement using speckle movements and phase gradients2013In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 52, no 10, article id 101912Article in journal (Refereed)
    Abstract [en]

    A new method to measure shape by analyzing the speckle movements in images generated by numerical propagation from dual-wavelength holograms is presented. The relationship of the speckle movements at different focal distances is formulated, and it is shown how this carries information about the surface position as well as the local slope of the object. It is experimentally verified that dual-wavelength holography and numerically generated speckle images can be used together with digital speckle correlation to retrieve the object shape. From a measurement on a cylindrical test object, the method is demonstrated to have a random error in the order of a few micrometers.

  • 19.
    Khodadad, Davood
    et al.
    Department of Physics and Electrical Engineering, Linnaeus University, Växjö, Sweden.
    Nordebo, Sven
    Department of Physics and Electrical Engineering, Linnaeus University, Växjö, Sweden.
    Seifnaraghi, Nima
    Department of Natural Sciences, Middlesex University, Hendon Campus, The Burroughs, London, United Kingdom.
    Yerworth, Rebecca
    Department of Medical Physics and Biomedical Engineering, University College London, London, United Kingdom.
    Waldmann, Andreas D.
    Swisstom AG, Landquart, Switzerland.
    Müller, Beat
    Swisstom AG, Landquart, Switzerland.
    Frerichs, Inéz
    Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany.
    van Kaam, Anton
    Emma Children's Hospital, Academic Medical Center, Department of Neonatology, Amsterdam, The Netherlands.
    Miedema, Martijn
    Emma Children's Hospital, Academic Medical Center, Department of Neonatology, Amsterdam, The Netherlands.
    Bayford, Richard
    Department of Natural Sciences, Middlesex University, Hendon Campus, The Burroughs, London, United Kingdom.
    The Value of Phase Angle in Electrical Impedance Tomography Breath Detection2018In: 2018 Progress in Electromagnetics Research Symposium (PIERS-Toyama), Electromagnetics Academy , 2018, p. 1040-1043Conference paper (Refereed)
    Abstract [en]

    The objective of this paper is to report our investigation demonstrating that the phase angle information of complex impedance could be a simple indicator of a breath cycle in chest Electrical Impedance Tomography (EIT). The study used clinical neonatal EIT data. The results show that measurement of the phase angle from complex EIT data can be used as a complementary information for improving the conventional breath detection algorithms.

  • 20.
    Khodadad, Davood
    et al.
    Department of Physics and Electrical Engineering, Linnaeus University, Växjö, Sweden.
    Tayebi, Behnam
    Department of Brain and Cognitive Engineering, Korea University, Seoul, South Korea.
    Shape Measurement Based on Combined Reduced Phase Dual-Directional Illumination Digital Holography and Speckle Displacements2018In: 2018 Progress in Electromagnetics Research Symposium (PIERS-Toyama), Electromagnetics Academy , 2018, p. 184-189Conference paper (Refereed)
    Abstract [en]

    We present a dual-directional illumination digital holographic method to increase height range measurement with a reduced phase ambiguity. Small change in the illumination angle of incident introduce phase difference between the recorded complex fields. We decrease relative phase difference between the recorded complex field 279 and 139 times by changing the angle of incident 0.5° and 1°, respectively. A two cent Euro coin edge groove is used to measure the shape. The groove depth is measured as ≈ 300μm. Further, numerical re-focusing and analysis of speckle displacements in two different planes are used to measure the depth without a use of phase unwrapping process.

  • 21.
    Nordehammar, Karl-Oskar
    et al.
    Örebro University, Department of Technology.
    Bergquist, Per
    Örebro University, Department of Technology.
    UTVECKLING AV EN KONDENSATORMIKROFON2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This degree thesis has been conducted at the University of Örebro and Västerdalarnas Mekaniska Industri AB (VMI) in Malung on behalf of Ehrlund Microphones. Ehrlund Microphones produce microphones with their patented capsule, containing a triangular membrane.During the course of this thesis, a new microphone model was under construction. The aim was to assist Ehrlund Microphones conducting tests, measurements and also coming up with ideas of how to improve the construction of the new microphone model.

    At VMI, where the capsules are produced, there is a lab designed to measure the frequency response of the capsules. The equipment in this lab has been installed and configured for the measurement method used, to verify the frequency response of the capsules.

    The conclusion of the examination whether the grille of the microphone influence the frequency response of the microphone in a noticeable way, is that the volume of air enclosed by the grille has greater influence on the frequency response than the shape of the grille.

    It’s most likely that the new transistor based microphone model will have an improved signal/noise-ratio, considering that the tests conducted in this essay were made on a prototype under development.

  • 22.
    Nyberg, Viktor
    Örebro University, School of Science and Technology.
    Ljudlokalisator2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a report of my thesis work carried out for Motion Control AB in Västerås. The task was to

    develop a prototype for a handheld sound localizator for the deaf. The project has involved working

    with everything from market research to soldering. The project includes both analog electronics as

    well as programming.

    Much time was spent on the preparatory work, maybe a little too much when it seemed like half the

    time was spent before I could get started and work. I managed to get a functional prototype except

    for the microphones, as they proved to be too sensitive to solder by hand. However, the project has

    been very educational and interesting.

  • 23.
    Otterskog, Magnus
    Örebro University, Department of Technology.
    Altering the amplitude statistics inside a scattered field chamberManuscript (preprint) (Other academic)
  • 24.
    Otterskog, Magnus
    Örebro University, Department of Technology.
    Antenna reflection coefficient measurements in a scattered field chamber2001Manuscript (preprint) (Other academic)
  • 25.
    Otterskog, Magnus
    Örebro University, Department of Technology.
    Environment simulations for MEG measurements inside reverberation chamberManuscript (Other academic)
  • 26.
    Otterskog, Magnus
    Örebro University, Department of Technology.
    Modelling of propagation environments inside a scattered field chamber2005In: IEEE 61st Vehicular technology conference, 2005. VTC 2005-Spring: Volume 1, 2005, p. 102-105Conference paper (Refereed)
    Abstract [en]

    Measurements on communication devices for evaluation of diversity and/or MIMO concepts must be made in the real environment or in a model of the real propagation environment. As a first step towards a complex, physical environment model the plane wave angular distribution, incident on the device under test (DUT), is altered in order to model plane wave angular distributions of real environments. Here a specialized reverberation chamber called the scattered field chamber (SFC) is used to create a source of Rayleigh faded plane waves and a shielded anechoic box with apertures is used to alter the angular distribution of the plane waves incident on the DUT. According to the measurements made, the model seems to be able to produce data that show agreement with measurements made on real propagation environments.

  • 27.
    Otterskog, Magnus
    Örebro University, Department of Technology.
    Polarization control in an scattered field chamberManuscript (preprint) (Other academic)
  • 28.
    Otterskog, Magnus
    Örebro University, Department of Technology.
    Propagation environment modeling using scattered field chamber2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis covers the development of the Reverberation Chamber as a measurement tool for cell phone tests in electronic production. It also covers the development of the Scattered Field Chamber as a measurement tool for simulations of real propagation environments.

    The first part is a more ”general knowledge about Reverberation Chambers”-part that covers some important phenomena like unstirred power and position dependence that might occour in a small Reverberation Chamber used for cell phone tests. Knowing how to deal with these phenomenas, give the possibility to use the chamber as a measurement tool for production tests even though it is too complex for a simple test of the antenna function.

    The second part shows how to alter some important propagation parameters inside the chamber to fit some real world propagation environments. The 3D plane wave distribution, the polarization and the amplitude statistics of the plane waves are all altered with simple techniques that are implementable all together. A small, shielded anechoic box with apertures is used to control 3D plane wave distribution and polarization. Antennas that introduce unstirred power in the chamber are used to control the statistics.

    List of papers
    1. Antenna reflection coefficient measurements in a scattered field chamber
    Open this publication in new window or tab >>Antenna reflection coefficient measurements in a scattered field chamber
    2001 (English)Manuscript (preprint) (Other academic)
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-3157 (URN)
    Note
    The 2001 Reverberation Chamber, Anechoic Chamber and OATS Users MeetingAvailable from: 2006-10-27 Created: 2006-10-27 Last updated: 2017-10-18Bibliographically approved
    2. Cell phone performance testing and propagation environment modelling in a reverberation chamber
    Open this publication in new window or tab >>Cell phone performance testing and propagation environment modelling in a reverberation chamber
    2003 (English)In: Proceedings of The 2003 Reverberation Chamber, Anechoic Chamber and OATS Users Meeting, 2003Conference paper, Published paper (Refereed)
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-3158 (URN)
    Conference
    The 2003 Reverberation Chamber, Anechoic Chamber and OATS Users Meeting, Austin, Texas
    Available from: 2006-10-27 Created: 2006-10-27 Last updated: 2017-10-18Bibliographically approved
    3. On creating a nonisotropic propagation environment inside a scattered field chamber
    Open this publication in new window or tab >>On creating a nonisotropic propagation environment inside a scattered field chamber
    2004 (English)In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 43, no 3, p. 192-195Article in journal (Refereed) Published
    Abstract [en]

    A traditional reverberation chamber creates a statistically isotropic test environment. Tests of communication devices may demand different environments to be able to test, for example, the influence of a diversity antenna. Here, a simple way of altering the distribution of plane waves incident on the device under test is presented. © 2004 Wiley Periodicals, Inc.

    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-3159 (URN)10.1002/mop.20417 (DOI)
    Available from: 2006-10-27 Created: 2006-10-27 Last updated: 2017-12-14Bibliographically approved
    4. Environment simulations for MEG measurements inside reverberation chamber
    Open this publication in new window or tab >>Environment simulations for MEG measurements inside reverberation chamber
    (English)Manuscript (Other academic)
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-3160 (URN)
    Available from: 2006-10-27 Created: 2006-10-27 Last updated: 2017-10-18Bibliographically approved
    5. The influence of stirrer size and chamber load on the number of uncorrelated samples created in a reverberation chamber
    Open this publication in new window or tab >>The influence of stirrer size and chamber load on the number of uncorrelated samples created in a reverberation chamber
    2005 (English)Manuscript (preprint) (Other academic)
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-3161 (URN)
    Note
    Proceedings of EMC Zürich 2005Available from: 2006-10-27 Created: 2006-10-27 Last updated: 2017-10-18Bibliographically approved
    6. Modelling of propagation environments inside a scattered field chamber
    Open this publication in new window or tab >>Modelling of propagation environments inside a scattered field chamber
    2005 (English)In: IEEE 61st Vehicular technology conference, 2005. VTC 2005-Spring: Volume 1, 2005, p. 102-105Conference paper, Published paper (Refereed)
    Abstract [en]

    Measurements on communication devices for evaluation of diversity and/or MIMO concepts must be made in the real environment or in a model of the real propagation environment. As a first step towards a complex, physical environment model the plane wave angular distribution, incident on the device under test (DUT), is altered in order to model plane wave angular distributions of real environments. Here a specialized reverberation chamber called the scattered field chamber (SFC) is used to create a source of Rayleigh faded plane waves and a shielded anechoic box with apertures is used to alter the angular distribution of the plane waves incident on the DUT. According to the measurements made, the model seems to be able to produce data that show agreement with measurements made on real propagation environments.

    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-3162 (URN)10.1109/VETECS.2005.1543258 (DOI)0-7803-8887-9 (ISBN)
    Conference
    IEEE 61st Vehicular technology conference. VTC 2005-Spring, 30 May-1 June
    Available from: 2006-10-27 Created: 2006-10-27 Last updated: 2017-10-18Bibliographically approved
    7. Polarization control in an scattered field chamber
    Open this publication in new window or tab >>Polarization control in an scattered field chamber
    (English)Manuscript (preprint) (Other academic)
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-3163 (URN)
    Available from: 2006-10-27 Created: 2006-10-27 Last updated: 2017-10-18Bibliographically approved
    8. Altering the amplitude statistics inside a scattered field chamber
    Open this publication in new window or tab >>Altering the amplitude statistics inside a scattered field chamber
    (English)Manuscript (preprint) (Other academic)
    National Category
    Other Electrical Engineering, Electronic Engineering, Information Engineering
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-3164 (URN)
    Available from: 2006-10-27 Created: 2006-10-27 Last updated: 2017-10-18Bibliographically approved
  • 29.
    Otterskog, Magnus
    Örebro University, Department of Technology.
    The influence of stirrer size and chamber load on the number of uncorrelated samples created in a reverberation chamber2005Manuscript (preprint) (Other academic)
  • 30.
    Otterskog, Magnus
    et al.
    Örebro University, Department of Technology.
    Madsén, Kent
    Cell phone performance testing and propagation environment modelling in a reverberation chamber2003In: Proceedings of The 2003 Reverberation Chamber, Anechoic Chamber and OATS Users Meeting, 2003Conference paper (Refereed)
  • 31.
    Otterskog, Magnus
    et al.
    Örebro University, Department of Technology.
    Madsén, Kent
    On creating a nonisotropic propagation environment inside a scattered field chamber2004In: Microwave and optical technology letters (Print), ISSN 0895-2477, E-ISSN 1098-2760, Vol. 43, no 3, p. 192-195Article in journal (Refereed)
    Abstract [en]

    A traditional reverberation chamber creates a statistically isotropic test environment. Tests of communication devices may demand different environments to be able to test, for example, the influence of a diversity antenna. Here, a simple way of altering the distribution of plane waves incident on the device under test is presented. © 2004 Wiley Periodicals, Inc.

  • 32.
    Pedersson, Cecilia
    Örebro University, School of Science and Technology.
    Automatiserad kalibrering av väderradar2009Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A calculator is used to calibrate all the weather radars in Sweden. One part of this thesis is to transfer the programs on this calculator to a PC. There is no documentation on how the calculator communicates with the radar, so the first step is to analyze and compare the code from the program with the information shown on a protocol analyzer. When the communication is known, a program is written in the language Agilent Vee. One program reads the response from the radar of a signal with different attenuation. Others calculates the radar constant, generates a calibration table and programs the table to the signal processor in the radar. By comparing the result from the programs on the PC and the corresponding results from the calculator it is verified that the programs run correctly.

    Saab Aerotech have found that the signal generator in not working correctly. The other part of this thesis is to automatically control the signal generator and a spectrum analyzer. The spectrum analyzer reads the power of a signal with different attenuation from the signal generator and presents the values in a graph. The curve of the graph is linear which means that there is no problem with the attenuation.

  • 33.
    Ranjbar, Parivash
    Örebro University, School of Science and Technology.
    Sensing the environment: development of monitoring aids for persons with profound deafness or deafblindness2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Earlier studies of persons with deafness (D) and/or deafblindness (DB) have primarily focused on the mobility and communication problems. The purpose of the present study was to develop technology for monitoring aids to improve the ability of persons with D and/or DB to detect, identify, and perceive direction of events that produce sounds in their surroundings.

    The purpose was achieved stepwise in four studies. In Study I, the focus was on hearing aids for persons with residual low frequency hearing. In Study II-IV, the focus was on vibratory aids for persons with total D.

    In Study I, six signal processing algorithms (calculation methods) based on two principles, transposition and modulation, were developed and evaluated regarding auditory identification of environmental sounds. Twenty persons with normal hearing listened to 45 environmental sounds processed with the six different algorithms and identified them in three experiments. In Exp. 1, the sounds were unknown and the subjects had to identify them freely. In Exp. 2 and 3, the sounds were known and the subjects had to identify them by choosing one of 45 sounds. The transposing algorithms showed better results (median value in Exp. 3, 64%-69%) than the modulating algorithms (40%-52%) did, and they were good candidates for implementing in a hearing aid for persons with residual low frequency hearing.

    In Study II, eight algorithms were developed based on three principles, transposition, modulation, and filtration – in addition to No Processing as reference, and evaluated for vibratory identification of environmental sounds. The transposing algorithms and the modulating algorithms were also adapted to the vibratory thresholds of the skin. Nineteen persons with profound D tested the algorithms using a stationary, wideband vibrator and identified them by choosing one of 10 randomly selected from the list of 45 sounds. One transposing algorithm and two modulating algorithms showed better (p<0.05) scores than did the No Processing method. Two transposing and three modulating algorithms showed better (p<0.05) scores than did the filtering algorithm. Adaptation to the vibratory thresholds of the skin did not improve the vibratory identification results.

    In Study III, the two transposing algorithms and the three modulating algorithms with the best identification scores in Study II, plus their adapted alternative, were evaluated in a laboratory study. Five persons from Study II with profound D tested the algorithms using a portable narrowband vibrator and identified the sounds by choosing one of 45 sounds in three experiments (Exp. 1, 2, and 3). In Exp. 1, the sounds were pre-processed and directly fed to the vibrator. In Exp. 2 and 3, the sounds were presented in an acoustic test room, without or with background noise (SNR=+5 dB), and processed in real time. Five of the algorithms had acceptable results (27%-41%) in the three experiments and constitute candidates for a miniaturized vibratory aid (VA). The algorithms had the same rank order in both tests in the acoustic room (Exp. 2, and 3), and the noise did not worsen the identification results.

    In Study IV, the portable vibrotactile monitoring aid (with stationary processor) for detection, identification and directional perception of environmental sounds was evaluated in a field study. The same five persons with profound D as in Study III tested the aid using a randomly chosen algorithm, drawn from the five with the best results in Study III, in a home and in a traffic environment. The persons identified 12 events at home and five events in a traffic environment when they were inexperienced (the events were unknown) and later when they were experienced (the events were known). The VA consistently improved the ability with regard to detection, identification and directional perception of environmental sounds for all five persons.

    It is concluded that the selected algorithms improve the ability to detect, and identify sound emitting events. In future, the algorithms will be implemented in a low frequency hearing aid for persons with low frequency residual hearing or in a fully portable vibratory monitoring aid, for persons with profound D or DB to improve their ability to sense the environment.

    List of papers
    1. Auditive identification of signal-processed environmental sounds: monitoring the environment
    Open this publication in new window or tab >>Auditive identification of signal-processed environmental sounds: monitoring the environment
    2008 (English)In: International Journal of Audiology, ISSN 1499-2027, E-ISSN 1708-8186, Vol. 47, no 12, p. 724-736Article in journal (Refereed) Published
    Abstract [en]

    The goal of the present study was to compare six transposing signal-processing algorithms based on different principles (Fourier-based and modulation based), and to choose the algorithm that best enables identification of environmental sounds, i.e. improves the ability to monitor events in the surroundings. Ten children (12-15 years) and 10 adults (21-33 years) with normal hearing listened to 45 representative environmental (events) sounds processed using the six algorithms, and identified them in three different listening experiments involving an increasing degree of experience. The sounds were selected based on their importance for normal hearing and deaf-blind subjects. Results showed that the algorithm based on transposition of 1/3 octaves (fixed frequencies) with large bandwidth was better (p<0.015) than algorithms based on modulation. There was also a significant effect of experience (p<0.001). Adults were significantly (p<0.05) better than children for two algorithms. No clear gender difference was observed. It is concluded that the algorithm based on transposition with large bandwidth and fixed frequencies is the most promising for development of hearing aids to monitor environmental sounds.

    Place, publisher, year, edition, pages
    London: Taylor & Francis, 2008
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering Medical Engineering
    Research subject
    Medicine; Electrical Engineering
    Identifiers
    urn:nbn:se:oru:diva-6995 (URN)10.1080/14992020802289776 (DOI)19085397 (PubMedID)
    Available from: 2009-05-28 Created: 2009-05-28 Last updated: 2018-10-31Bibliographically approved
    2. Vibrotactile identification of signal-processed sounds from environmental events
    Open this publication in new window or tab >>Vibrotactile identification of signal-processed sounds from environmental events
    2009 (English)In: Journal of rehabilitation research and development, ISSN 0748-7711, E-ISSN 1938-1352, Vol. 46, no 8, p. 1021-1036Article in journal (Refereed) Published
    Abstract [en]

    Objective: To compare three different signal-processing principles (eight basic algorithms), transposing, modulating and filtering, and to find the principle(s)/al­go­rithm(s) that result in the best tactile identification of environmental sounds.

    Subjects: Nineteen volunteers (9F/10M), deaf or profoundly hearing impaired, between 18-50 yr. 

    Method: Sounds produced by 45 representative en­vi­ron­men­tal events were processed using the different al­go­rithms and presented to subjects as tactile stimuli using a wide-band stationary vibrator. Eight algorithms based on the three principles (one un­pro­cessed, used as reference) were compared. The subjects iden­ti­fied the sti­mu­li by choo­sing one among ten alter­na­tives drawn from the 45 events. 

    Result and conclusion: Algorithm and subject were significant (RM-ANOVA, p<0.001) factors affecting the results. There were also large differences between individuals regarding which algorithm was best. The test-retest variability was small (Mean±95%CI: 8±3 percentage units), and no correlation between identification score and individual vibratory thresholds was found. One transposing al­go­rithm and two mo­du­lating al­go­rithms led to significantly (p<0.05) better results than did the unprocessed signals. Thus, the two principles of transposing and modulating were appropriate, whereas filtering was unsuccessful. In future work, the two transposing algorithms and the modulating algorithms will be used in tests with a portable vibra­tor for the deafblind.

    Keywords
    Deafblind, Environmental sound, Identification, Monitoring, Perception, Tactile, Transposing, Vibration
    National Category
    Signal Processing
    Research subject
    Electronics
    Identifiers
    urn:nbn:se:oru:diva-8126 (URN)10.1682/JRRD.2008.11.0150 (DOI)000274171000005 ()20157859 (PubMedID)2-s2.0-75749141318 (Scopus ID)
    Projects
    Sensing the environment
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2018-10-31Bibliographically approved
    3. Vibrotactile identification of signal-processed sounds from environmental events presented by a portable vibrator: a laboratory study
    Open this publication in new window or tab >>Vibrotactile identification of signal-processed sounds from environmental events presented by a portable vibrator: a laboratory study
    2009 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Objective: To evaluate different signal-processing algorithms for tactile identification of environmental sounds in a monitoring aid for the deafblind.

    Subjects: Two men and three women, sensorineurally deaf or profoundly hearing impaired with experience of vibratory experiments, age 22-36 years.

    Method: A closed set of 45 representative environmental sounds were processed using two transposing (TRHA, TR1/3) and three modulating algorithms (AM, AMFM, AMMC) and presented as tactile stimuli using a portable vibrator in three experiments. The algorithms TRHA, TR1/3, AMFM and AMMC had two alternatives (with and without adaption to vibratory thresholds). In Exp. 1, the sounds were preprocessed and directly fed to the vibrator. In Exp. 2 and 3, the sounds were presented in an acoustic test room, without or with background noise (SNR=+5 dB), and processed in real time.

    Results: In Exp. 1, Algorithm AMFM and AMFM(A) consistently had the lowest identification scores, and were thus excluded in Exp. 2 and 3. TRHA, AM, AMMC, and AMMC(A) showed comparable identification scores (30%-42%) and the addition of noise did not deteriorate the performance.

    Conclusion: Algorithm TRHA, AM, AMMC, and AMMC(A) showed good performance in all three experiments and were robust in noise; they can therefore be used in further testing in real environments.

    Keywords
    Environmental sound, Identification, Narrow-band, Tactile perception, Transposing, Vibration, Vibrator
    National Category
    Signal Processing Engineering and Technology Computer and Information Sciences
    Research subject
    Signal Processing
    Identifiers
    urn:nbn:se:oru:diva-8129 (URN)
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2018-01-13Bibliographically approved
    4. Vibrotactile detection, identification and directional perception of signal-processed sounds from environmental events: a pilot field evaluation in five cases
    Open this publication in new window or tab >>Vibrotactile detection, identification and directional perception of signal-processed sounds from environmental events: a pilot field evaluation in five cases
    Show others...
    2009 (English)In: Iranian Rehabilitation Journal, ISSN 1735-3602, Vol. 6, no 7-8, p. 89-107Article in journal (Refereed) Published
    Abstract [en]

    Objective: Conducting field tests of a vibrotactile aid for deaf/deafblind persons for detection, identification and directional perception of environmental sounds.

    Method: Five deaf (3F/2M, 22–36 years) individuals tested the aid separately in a home environment (kitchen) and in a traffic environment. Their eyes were blindfolded and they wore a headband and holding a vibrator for sound identification. In the headband, three microphones were mounted and two vibrators for signalling direction of the sound source. The sounds originated from events typical for the home environment and traffic. The subjects were inexperienced (events unknown) and experienced (events known). They identified the events in a home and traffic environment, but perceived sound source direction only in traffic.

    Results: The detection scores were higher than 98% both in the home and in the traffic environment. In the home environment, identification scores varied between 25%-58% when the subjects were inexperienced and between 33%-83% when they were experienced. In traffic, identification scores varied between 20%-40% when the subjects were inexperienced and between 22%-56% when they were experienced. The directional perception scores varied between 30%-60% when inexperienced and between 61%-83% when experienced.

    Conclusion: The vibratory aid consistently improved all participants’ detection, identification and directional perception ability.

    Place, publisher, year, edition, pages
    Tehran: University of social welfare and rehabilitation sciences Evin, 2009
    Keywords
    Deaf, Deafblind, Directional perception, Environmental sound, Tactile perception
    National Category
    Signal Processing Other Health Sciences
    Research subject
    Electronics; Disability Science
    Identifiers
    urn:nbn:se:oru:diva-8131 (URN)
    Projects
    Sensing the environment
    Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-10-18Bibliographically approved
  • 34.
    Ranjbar, Parivash
    et al.
    Örebro University, School of Health and Medical Sciences, Örebro University, Sweden. Örebro University Hospital, Örebro, Sweden.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Akner-Koler, Cheryl
    University Collage of Arts (Konstfack), Stockholm, Sweden.
    Borg, Erik
    Örebro University Hospital, Örebro, Sweden.
    Haptic Technical Aids for EnvironmentalPerception, Time Perception and Mobility (in a Riding Arena) for Persons with Deafblindness2014In: HAPTICS: NEUROSCIENCE, DEVICES, MODELING, AND APPLICATIONS, PT II, Springer Berlin/Heidelberg, 2014, Vol. 8619, p. 488-490Conference paper (Other academic)
    Abstract [en]

    This demonstration presents three vibrotactile aids to support personswith deafblindness. One aid, Monitor, consists of a microphone that detectssounds from events which are then processed as a signal that is adapted to thesensitivity range of the skin. The signal is sent as vibrations to the user withdeafblindness, who can interpret the pattern of the vibrations in order to identifythe type and position of the event/source that produced the sounds. Another aid,Distime, uses a smart phone app that informs the user with cognitive impairmentand deafblindness about a planned activity through; audio, visual or tactileinteraction that is adapted to the abilities of each individual. The last aid, Ready-ride, uses two smart phones and up to 11 vibrators that help the horse back riderwith deafblindness to communicate with the instructor from a distance viavibrators placed on different parts of the riders body e.g. wrist, thigh, back, ankle.

  • 35.
    Salamati, Mahnaz
    et al.
    Örebro University, Department of Technology.
    Stranneby, Dag
    Örebro University, Department of Technology.
    Electromagnetic signatures as a tool for Connectionless Test (CT)2002Conference paper (Other academic)
    Abstract [en]

    Today’s electronic products and subassemblies are highly integrated, miniaturized devices having complex functionality. Final test and troubleshooting using conventional test points, probes and bed-of-nails techniques are becoming harder, and are in many cases not even possible. Further, due to increasing production volumes, the time needed for testing is a critical factor. An alternative way to test a device is to employ Connectionless Test (CT). The idea is to measure the electromagnetic (EM) field surrounding the DeviceUnder Test (DUT) during different modes of operation.Using the CAD data for the DUT, an Electromagnetic signature can be created from the measured EM data.The obtained signature is matched to earlier signatures stored in an adaptive database that is being updated continuously. The database not only contains signatures from “known good” devices, but also signatures obtained from some typical failure types. In this way, the DUT can be classified as working properly, suffering from a previously known type of failure or having a “new”, hitherto unknown malfunction. Since the electromagnetic signature also contains spatial information, it is an interesting tool in thetroubleshooting process. Besides the type of failure, an estimate of the location of the problem may be extracted from the signature. Initial practical tests have shown that the CT method outlined above works for both “analog” as well as “digital” electronic products having medium complexity.

  • 36.
    Samadi, Mahnaz
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Connectionless Testing2005Conference paper (Other academic)
  • 37.
    Samadi, Mahnaz
    et al.
    Örebro University, School of Science and Technology.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Electromagnetic signatures for Test and Troubleshooting2003Conference paper (Other academic)
  • 38.
    Sjödahl, Mikael
    et al.
    Luleå University of Technology, Lkuleå, Sweden.
    Hallstig, Emil
    Optronic, Sekellefteå, Sweden.
    Khodadad, Davood
    Luleå University of Technology, Lkuleå, Sweden.
    Multi-spectral speckles: theory and applications2012In: Speckle 2012: V International Conference on Speckle Metrology / [ed] Ángel Fernandez Doval & Cristina Trillo, SPIE - International Society for Optical Engineering, 2012, Vol. 8413, article id 841306Conference paper (Refereed)
    Abstract [en]

    The objective of this paper is to discuss the properties and a few applications of multi-spectral speckles. The paper starts with a theoretical section where the correlation properties of multi-spectral speckles are detailed for the case of reflective imaging geometry. Both a free-space geometry and an imaging geometry are detailed. As an application example effects and possibilities provided by the theory in a measurement of surface shape of a generally shaped object from a dual-wavelength holographic recording are detailed. It is showed that the same phase profile is obtained from integration of speckle movements and phase unwrapping and they are therefore exchangeable quantities.

  • 39.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Contactless EMI/EMC testing at PC board level2004Conference paper (Other academic)
  • 40. Stranneby, Dag
    ESD risks in industrial environments2013In: Electronic environment, no 4, p. 10-13Article in journal (Other academic)
    Abstract [en]

    The risks caused by Electrostatic discharges (ESD), where electronic components may be damaged in Electronic production and testing facilities, are well known. ESD however, also presents problems and major risk in many other industrial environments, for instance Chemical Process plants. This presentation is an overview of ESD related problems in general.

  • 41.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    Mätmetoder och problem2009In: Electronic environment, no 4, p. 26-30Article in journal (Other academic)
    Abstract [sv]

    Vid ESD-skyddsarbete har man ofta behov av att mäta till exempel laddning, potential, spänning, kapacitans och resistans. Ofta handlar det om höga spänningar, små laddningar, små kapacitanser och höga resistanser. Etablerade metoder och instrument finns, men hur noggranna är dessa, och vad mäter man egentligen? I denna genomgång av metoder och instrument belyses mättekniska begränsningar och felkällor som kan ställa till problem, och i värsta fall göra mätningarna oanvändbara.

  • 42.
    Stranneby, Dag
    Örebro University, School of Science and Technology.
    What color is the Electron?2007Conference paper (Other (popular science, discussion, etc.))
  • 43.
    Stranneby, Dag
    et al.
    Örebro University, School of Science and Technology.
    Borg, Erik
    Örebro University Hospital, Örebro, Sweden.
    Ready-ride: A positioning and signaling system to support autonomous riding for the deaf-blind (R&L)2007In: 14th Deafblind International World Conference 25th–30th September 2007 Burswood Convention Centre Perth, Western Australia, Australia. Conference Proceedings: Breaking the isolation, 2007, p. 737-740Conference paper (Other academic)
    Abstract [en]

    Horse riding is a popular sport among young deaf people in Sweden. A gradual decrease in visual acuity is also not very uncommon, and thus some young horse enthusiasts encounter increasing difficulties in performing their favorite sport with autonomy. In collaboration with Segersjö Fälttävlan, a system has been designed and tested at Ahlsén Research Institute to provide position information in the riding school and vibratory transmitted information to support the rider’s orientation.There are two alternative positioning systems. One is based on a fixed sensing system localizing the rider. In the other system, the instructor provides the position using a hand-held PC with a simple point-and-click interface. The position of the rider is indicated on the screen pointer or a mouse. The information is coded in different ways. Three alternatives are being considered at present. First, the deviation from the pre-determined route is indicated in terms of both angular deviation and distance. Second, the change in direction needed to return to the route is indicated. Third, the conventional letter codes are indicated by signaling the angular deviation to the closest letter at each point in time.The information is transferred to nine vibrators, localized on a waist belt or a headband. Experiments where the rider is wearing a vest with vibrators on the back, is also in progress. In the communicating system using pre-determined instructions, instructions are given using one- or two-letter Morse codes. With the presented construction, the system can be used in a riding school that has a fixed positioning system mounted or in any riding school by using the instructor-controlled positioning system.

  • 44.
    Stranneby, Dag
    et al.
    Örebro University, School of Science and Technology.
    Salamati, Mahnaz
    Örebro University, School of Science and Technology.
    Connectionless Test (CT) using Electromagnetic Signature2002In: Proceedings : the IMAPS Nordic Annual Conference: Stockholm, 2002, 29 September-2 October 2002, 2002, p. 83-86Conference paper (Other academic)
  • 45.
    Sundberg, Daniel
    Örebro University, Department of Technology. Örebro University, School of Science and Technology.
    HANDSFREE-ENHET FÖR MOBIL TRYGGHETSTELEFON2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Cnior Mobile AB i Lindesberg utvecklar en mobil trygghetstelefon för äldre. Detta examensarbete går ut på att utforma en handsfree-enhet för denna. Handsfree-enheten ska integreras i larmknappen, som bärs av användaren runt handleden, och har kontakt med telefonen via blåtandsradio. I examensarbetet ingår att välja ut lämplig högtalare och mikrofon, hitta lösningar för smuts- och vattentålighet samt att lösa problem med ekon och bakgrundsstörningar.

    En högtalare hittades som uppfyllde kraven för smuts- och vattentålighet samtidigt som den hade utmärkt frekvensgång för återgivning av tydligt tal. Vattenavrinning från högtalaren löstes genom att ett sinussvep sänds ut från högtalaren varje gång ett samtal ska kopplas upp. På så sätt pressar ljudtrycket ut vattnet från handledsknappens kavitet. Olika utformningar av ljudhålen i handledsknappens skal provades. Den bästa lösningen för vattenavrinningen var att använda sju stycken runda hål med 1,3 mm i diameter. En ljudtrycksmätning säkerställde att ljudtrycket inte blev lidande av denna utformning av ljudhålen.

    Ekosläckning och bakgrundsstörningsundertryckning sköts av GSM-modulen i trygghetsmobilen. I ekosläckningens manual finns beskrivet hur ekosläckningens 24 parametrar kan justeras för att passa olika applikationer. Endast en mindre ändring av de rekommenderade parametervärdena behövdes för att ekosläckning och bakgrundsstörningsundertryckning skulle fungera tillfredställande.

    Eftersom mikrofonernas datablad visade på så snarlika egenskaper överlämnades mikrofonvalet till företaget, då det kan vara klokt att låta priset avgöra.

  • 46.
    Sørensen, Mads Peter
    et al.
    Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark.
    Falsig Pedersen, Niels
    Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark.
    Ögren, Magnus
    Örebro University, School of Science and Technology.
    The dynamics of magnetic vortices in type II superconductors with pinning sites studied by the time dependent Ginzburg–Landau model2017In: Physica. C, Superconductivity, ISSN 0921-4534, E-ISSN 1873-2143, Vol. 533, p. 40-43Article in journal (Refereed)
    Abstract [en]

    We investigate the dynamics of magnetic vortices in type II superconductors with normal state pinning sites using the Ginzburg–Landau equations. Simulation results demonstrate hopping of vortices between pinning sites, influenced by external magnetic fields and external currents. The system is highly nonlinear and the vortices show complex nonlinear dynamical behaviour.

  • 47.
    Ögren, Magnus
    Örebro University, School of Science and Technology.
    Övningsuppgifter, Ellära för civilingenjörer2018Book (Other academic)
  • 48.
    Ögren, Magnus
    et al.
    Dept. of Mathematics, Technical University of Denmark, Kongens Lyngby, Denmark.
    Sørensen, M. P.
    Dept. of Mathematics, Technical University of Denmark, Kongens Lyngby, Denmark.
    Pedersen, N. F.
    Dept. of Mathematics, Technical University of Denmark, Kongens Lyngby, Denmark.
    Self-consistent Ginzburg-Landau theory for transport currents in superconductors2012In: Physica. C, Superconductivity, ISSN 0921-4534, E-ISSN 1873-2143, Vol. 479, p. 157-159Article in journal (Refereed)
    Abstract [en]

    We elaborate on boundary conditions for Ginzburg-Landau (GL) theory in the case of external currents. We implement a self-consistent theory within the finite element method (FEM) and present numerical results for a two-dimensional rectangular geometry. We emphasize that our approach can in principle also be used for general geometries in three-dimensional superconductors. © 2012 Elsevier B.V. All rights reserved.

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